Support-device for the crystal of an x-ray spectrometer



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SUPPORT-DEVICE FOR THE CRYSTAL OF AN X-RAY SPECTROMETER Filed Aug. 3l,'1965 r 2 Sheets-Sheet 1 Fig.1

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Oct. 27, 1970 SUPPORT-DEVICE FOR THE CRYSTAL OF AN X-RAY SPECTROMETER Iz 2 Sheets-Sheet 2 Filed Aug 51, 1966 Y 12 n v I IL I i 13a H Imp lla lI m v v VENTQRS I Werner Spec/ United States Patent 3,536,912SUPPORT-DEVICE FOR THE CRYSTAL OF AN X-RAY SPECTROMETER Werner Speck,Bietigheim, and Fritz Kastner, Karlsruhe,

Germany, assignors to Siemens Aktiengesellschaft,

Munich, Germany, a corporation of Germany Filed Aug. 31, 1966, Ser. No.576,444 Claims priority, applicatigrgl ggrmany, Sept. 16, 1965,

Int. (:1. (26111 23/20 US. Cl. 250-515 Claims ABSTRACT OF THE DISCLOSUREAs is well known, the crystals in X-ray spectrometers are relativelysensitive so that they can be easily damaged and consequently anexchange of the crystal freqeuntly is required. The various individualexaminations also require different crystals. In known supportingdevices for the crystals in X-ray spectrometers, the crystal exchangerequires a new adjustment of the crystal, which is undesirable for thereason that it has to be undertaken by the user of the X-rayspectrometer who often is not experienced in such operations. This iscorrespondingly true with regard to the support of curved monochromaticcrystals, as well as samples.

The invention is directed to a supporting device, particularly for thesupport of the crystal of an X-ray spectrometer and solves the problemof creating a supporting device which avoids the necessity of anadjustment in the spectrometer. A device, according to the invention,which solves this problem is characterized in that the crystal isrigidly mounted, in customary manner, in a first mounting whic hin turnis inserted in a second mounting in an adjustable manner in such a waythat its ranges of reflection of the X-rays have a definable position inrelation to the base of the second mounting, remote from the mountedcrystal, and that in the spectrometer a crystal holder, with a supporttable for the receiving and mounting of the base of the second mounting,is provided which occupies a predetermined position with respect to thesample and the detectors of the spectrometer. As a result of thesefeatures, an adjustment is obtained of all parts relative to therotation axis of the spectrometer.

In the supporting device, according to the invention, all of theadjustment processes may be completed by the manufacturer of theinstrument at the factory. For example, the crystal mounted in customarymanner can be adjusted in the second mounting in a device at the factoryrelative to the base of the second mounting remote from the crystal, andthe support table of the crystal holder in the X-ray spectrometer islikewise completely adjusted by the manufacturer with regard to itsposition, i.e., with regard to its position as well as with regard toits inclination relative to the sample and to the detectors of thespectrometer, and also for example, to the counting tubes.

Consequently, while the crystal is rigidly cemented in a known mannerinto the first mounting or is glued into such mounting or rigidlyattached to such mounting in another manner, the crystal so mounted issupported in the second mounting in an adjustable manner. This may beaccomplished by the feature that adiustment screws and cooperaice.

ble springs are provided. Expediently, these elements are disposed inbores in peripheral portions of the first mounting. Consequently, thefirst mounting laterally surrounds the crystal, with its edge portionsappropriately constructed with sufiicient width to accommodate theadjusting screws and cooperable springs.

The base of the second mounting remote from the mounted crystal and thesupporting table on the crystal holder must be brought into a specificposition relative to each other, and in a preferred form of theinvention this is accomplished in such a manner that the base of thesecond mounting remote from the mounted crystals, which forms thereference plane for the adjustment of the crystal within its mounting,and/or the supporting table of the crystal holder which presents adefined position relative to the elements of the spectrometer, isprovided with magnets and that the other cooperable member consists of aparamagnetic material. In the magnetic retention of the second mountingand crystal on the supporting table of the crystal holder, the magnetsmay be flush with the respective plane of the table, whereby the entiretable actually defines the supporting plane. However, it is alsopossible to let the magnets extend outwardly from the actual tableplane, in which case the magnets can be held by means of adjustingscrews which serve for the adjustment of the supporting plane, i.e., ofthe base of the second mounting.

Since the magnetic attraction is effective primarily in the direction ofthe lines of the magnetic field, it will be as a rule desirable toprovide lateral stops in the support plane for the second mounting andthe associated mounted crystals;

Often there is the desire or requirement to be able to selectively bringany of several crystals into operating position. The supporting deviceaccording to the invention meets this requirement if the crystal holdercontains as crystal changer several supporting tables in a drum-likeassembly or turret which is so arranged that it may rotate about theaxis of its shaft, which may be connected to suitable drive means. Theturret can be so adjusted at the factory that all support planes, whenswung into operating position, possess the specific required positionrelative to the sample and to the detectors of the spectrometer.

If the instrument involved is an X-ray spectrometer with detectors thatmay be swung around an axis, this axis expediently is at leastapproximately perpendicular to the direction of the axis of the drum orturret of the crystal holder, since in this case play in the operatingposition of the individual crystals with respect to the ability ofreproducing the analysis, does not have such a pronounced effect.

In order to control which crystal is in the operating position andwhether the swinging motion has been completed, cam means for theoperation of contacts may be associated with the turret, which aredisposed in suitable circuits for maintaining the turret in position.

In the following the invention is explained in geater detail by means ofthe example of construction illustrated in the figures, wherein likereference characters indicate like or corresponding parts, and in which:

FIG. 1 is a top plan view of a crystal setting embodying the invention;

FIG. 2 is an end elevation of the structure illustrated in FIG. 1 with aportion broken away to show the details thereof;

FIG. 3 is a side view of a crystal holder, constructed as a crystalchanger; and

FIG. 4 is a front view of the structure of FIG. 3 with portions brokenaway to show the details thereof.

Referring to FIGS. 1 and 2, the reference numeral 1 designates thecrystal which is rigidly held, in known manner. in a first mounting 3,for example, by gluing or cementing, the glue recesses or bores 2 beingprovided for the purpose. The crystal so mounted is now assembled in asecond mounting 4 in an adjustable manner. In order to obtain thedesired adjustability, the mounted crystal is not rigidly disposed inthe second setting, but is adjustably retained by means of adjustingscrews 5 and cooperable compression springs 6 in a more or lesssuspended manner within the second mounting 4. As is apparent from theto pview of FIG. 1, three adjusting screws 5 are provided in thisembodiment to avoid static uncertainties. As particularly illustrated inthe front view of FIG. 2, partially shown in section, the adjustingscrews 5 and the compression springs 6 are disposed in thelongitudinally extending peripheral portions of the first mounting whichhave been appropriately constructed with a corresponding widthsufficient to accommodate bores in which the respective springs areretained, the screws 5 being threaded into the bottom 7 of the secondmounting 4.

The parts 5 and 6 serve for the adjustment of the ranges of the crystal1 reflecting the X-rays to bring them into a defined position relativeto the base member 8 of the second mounting 4 disposed at the side ofthe setting 1 remote from the mounted crystal. This base cooperates withsupporting means at the crystal holder in the spectrometer, saidsupporting means likewise being adjustable relative to the sample and tothe detectors of the spectrometer, which adjustment would befactory-set.

An example of construction for a sample holder in the form of a changer,according to the invention, is illustrated in FIGS. 3 and 4. The crystal1 is not illustrated in FIG. 4 in order to clearly disclose a supportingtable 10 therefor. Such support table carries permanent magnets 11 whichserve for the retention of the second mounting 4 (see FIGS. 1 and 2)carrying the mounted crystal. In accordance therewith, at least thebottom 7 of the second mounting 4 is constructed of a paramagneticmaterial. In the crystal holder illustrated in FIGS. 3 and 4, themagnets 11 extend outwardly from the plane of the supporting table 10,and accordingly define the actual support plane for the base member 8 ofthe second crystal mounting 4. In order to provide the possibility of asimple adjustment for such magnets, they may be retained in operativeposition on the table 10 by means of screws. Accordingly, in FIG. 4 theadjusting screws 12 illustrated are associated with those permanentmagnets attached to the support table which is opposite to the visiblesupport table 10 in the installation represented in FIGS. 3 and 4.

In order to provide security against a lateral sliding of the crystalmountings, retained only by magnetic force, rigid stops or catches 13and 13a and resilient catches 14 are attached to the individualsupporting tables. In this construction the rigid catches 13 servesimultaneously for the operating of contact means 15 which areoperatively disposed in mounting circuits, and enable the determinationas to whether the crystal has swung into operating position, i.e., todetermine whether the swinging motion thereof is completed.

As already mentioned several times, the installation illustrated inFIGS. 3 and 4 is a crystal changer with several crystals. Theillustrated crystal holder may be supplied with four crystals of whichin FIG. 3 only one designated by the numeral 1 is schematicallyillustrated. The supporting tables for the reception of the crystal, ofwhich only the one designated by the numeral 10 is visible, in FIG. 3,are combined in a drum-like manner by oppositely disposed pairs. Thisdrum-like configuration or turret may be rotated around the axis of theturret shaft 16 by means of gearing comprising the respective gears 17to 21 and the coupling 22 by means of a motor (not shown). In order toretain the axis of the rotating shaft 16 and the supporting table 10rotatable therewith into operating position, in a defined positionrelative to the sample and to the detectors of the spectrometer, aspecial bearing for the rotatable shaft 16 is provided, whereby thebearing play is as small as possible, the shaft 16 being urged into therecess 24 of the bearing block 25 by means of a spring 23. The axis ofthe shaft 16 is perpendicular to the direction of the pivotal axis 26 ofthe spectrometer.

The invention is not limited to the examples of construction illustratedin the figures. For example, the crystal holder may be constructed forthe reception of only a single crystal or for the reception of more thanfour crystals. A different number of adjusting screws and cooperablesprings for the support of the mounted crystal in the second mountingmay be employed, without departing from the principle, according to theinvention, of the adjustment of the crystal relative to a plane formedby its mounting on the one hand, and of the creation of a support tablehaving a defined position relative to the sample and to the detectors atthe crystal holder in the X-ray spectrometer on the other hand, as wellas the fact that these tWo structures can be assembled without requiringany subsequent adjustment. The invention obviously may also be utilizedin connection with the support of monochromatic crystals and samples.

Changes may be made within the scope and spirit of the appended claimswhich define what is believed to be new and desired to have protected byLetters Patent.

We claim:

1. In combination, a spectrometer having a crystal holder supportingtable associated therewith, the said supporting table having a setposition relative to the position of the sample to be examined by thespectrometer and to the detectors of the spectrometer, and a crystalsupporting device comprising a first mounting member in which aspectrometer crystal is adhesively retained, a second mounting memberhaving a base surface thereon, said first mounting member inserted insaid second mounting member in a defined position whereby the ranges ofrefiection of X-rays by said crystal have a defined position relative tothe said base of the said second mounting member, said first memberadjustably retained in said second member so as to allow movement ofsaid first member with respect to said second member to obtain saiddefined position and said second member adapted to be retained againstthe said crystal holder supporting table in a preset position relativeto the supporting table and base surface.

2. The apparatus of claim 1 wherein the said first member is adjustablyretained in the said second member by means of compressible springsentrapped between the said two members and adjustable screws connectingthe said two members adapted to force the said two members togetheragainst the contra-acting force of the said springs.

3. The apparatus of claim 2 wherein the adjustable screws andcompressible springs are disposed in bores located in peripheralportions of the first mounting member.

4. The apparatus of claim 1 wherein cooperable magnetic means areprovided in association with the said crystal holder supporting tableand the said second mounting for retaining the said second mounting andtable in assembled relation by magnetic attraction.

5. An assembly according to claim 4 wherein said cooperable magneticmeans provided on the supporting table and second mounting membercomprise magnets carried by one cooperable with a paramagnetic portionof the other.

6. An assembly according to claim 5 wherein said magnets extendoutwardly from the plane of their supporting member and are retained inoperative position by means of adjusting screws.

7. An assembly according to claim 1 wherein the said crystal holdersupporting table is in the form of a crystal changer containing aplurality of individual crystal supporting tables in a turretarrangement, and drive means operatively connected to the turret bymeans of which it may be rotated about its axis to sequentially presentindividual supporting tables at an operating position with respect tothe other elements of the spectrometer.

8. An apparatus according to claim 7 wherein the spectrometer isequipped with detectors which may be swung around an axis and in whichthe turret arrangement is rotatable about an axis extendingsubstantially perpendicular to the direction of the rotational axis ofsaid detectors.

9. The apparatus according to claim 8 including lateral catches carriedby the individual supporting tables for positioning the second mountingmembers thereon.

10. The apparatus according to claim 9 including cam means on the turretarranged to operate contacts in a monitoring circuit for indicating theposition of the turret arrangement.

References Cited UNITED STATES PATENTS 2,540,821 2/1951 Harker 250-51153,124,681 3/1964 Zingaro 25051.5 3,177,360 4/1965 Hague et a1. 25051.5

OTHER REFERENCES Micro X-Ray Diffraction Camera for Studies ofOrientation Textures and Single Microcrystals, J. E. Glas,

10 Journal of Scientific Instruments, v01. 39, 1962, pp. 60-

ARCHIE R. BORCHELT, Primary Examiner C. E. CHURCH, Assistant Examiner

